1. Technical Field of the Invention
The present invention relates generally to a coil wire for a coil assembly of a rotating electrical machine.
2. Background Art
As a conventional process of manufacture of a coil assembly of rotating electrical machines, for example, as shown in Japanese patent first publication No. 2002-176752, a method of simultaneously coiling a plurality of coil wires with use of a pair of a plate-like coil core facing each other is known.
Additionally, as shown in Japanese patent first publication No. 2004-104841, by repeating a first coiling process, advancing process and second coiling process, a method of coiling a plurality of coil wires is known in which one coil wire is braided to the other coil wire with 90 degrees twist. The first coiling process is that one coil wire is coiled only 90 degrees about an axis relative to the other coil wire which is formed in a triangle-wave-shape. The advancing process is that one coil wire is accumulated in only half of the turned portion so that the more coil wires are overlapped. The second coiling process is that one coil wire is further coiled only 90 degrees about the axis.
As methods of braiding a plurality of the coil wires which is formed in a plurality of turn portions with each other, the following methods are known.
In the first known method, as carried out by a known winding machine, one coil wire is revolved around the other fixed coil wire, and the coil wire is moved in a longitudinal direction of the coils of one coil pitch per one revolution. This first method is known.
In the second known method, a position of braiding two coil wires is centrally held with a predetermined angle, and each of the coil wires is revolved around the other coil wire respectively.
In the case of braiding for example twelve coil wires for producing a coil assembly of three-phase coil wires, a method is known where two coil-wire-bundles each having six bundled coil wires are bundled by these first and second methods.
As shown in FIG. 9, a conventional coil wire bunch 80 is braided such that each of the coil wires 81 is mutually offset in the axial direction thereof and intersects, respectively. The coil wires 81 have a turn portion 82 and a straight slot-accommodated-portion 83. Each of the turn portions 82 and each of the slot-accommodated-portions 83 are aligned at every predetermined spacing, respectively.
In the case of braiding two coil wire bunches 80, a spacing “b” between coil wire bunches 80 which are braided to the other coil wire bunches 80 is narrowed, and the spacing necessary for braiding is not sufficient.
In addition, the spacing “b” of the other coil wire bunches 80 is narrowed by increasing of the number of coil wires used in the coil wire bunches 80.
Furthermore, when the spacing “b” of the other coil wire bunch 80 is expanded, an aligned condition of the coil wires needs to be broken.
In this case, after the two coil-wire-bunches 80 are braided, a restoring process which restores the initial aligned condition is needed. Further, this restoring process is likely to develop a problem such as interference between each of the coil wires and scratching, thus the slot-accommodated-portions may be deformed thereby. Due to deforming the coil wires when the braided coils are formed in an awkward shape, a desired coil assembly is unable to be obtained.